Rising global demand for cleaner energy from biomass could drive more land acquisition in poorer nations where food security and land rights are weak, an International Institute for Environment and Development report said today.

"If left unchecked, the growing pressure on land access could undermine livelihoods and food security in some of the world's poorest countries," the London-based nonprofit research group said, calling for more public scrutiny into global biomass expansion plans.

Biomass energy makes up 77 percent of world renewable energy, and trees and woody plants account for 87 percent of that biomass, the report said.

As governments attempt to move away from fossil fuel-based power, they are increasingly looking at biomass, as new technologies now allow it to be converted competitively into liquid fuels and electricity.

In Britain alone, plans to expand biomass energy will push demand for biomass up to as much as 60 million tonnes a year, compared with 1 million tonnes burned or co-fired in the country's biomass power stations today, according to the IIED.

Local sourcing, such as using wood from forests near power plants, is favored by countries such as Germany, France, and the United States, the report said.

However, with demand for wood set to outstrip supply by up to 600 percent in some countries, and high tree growth rates in tropical countries, it is likely that some developed countries will look at nontraditional suppliers in the South to plug the biomass gap, the IIED added.

Already, operators in Brazil are becoming more interested in exporting wood chips to Europe, while Africa is also likely to play an important role in feeding European demand.

"All eyes are turned to food and biofuels, but tree plantations for biomass energy may soon become an important driver in the global land rush," said Lorenzo Cotula, a senior researcher at IIED and co-author of the report.

Investing in biomass plantations could become more attractive in the coming years as fossil fuel prices rise and the cost of biomass production falls as new production methods develop, the report said.

Biomass plantations may also be able to generate additional revenue streams, such as by selling carbon credits.

However, in the search for cheap land, suitable climates, and competitive transport costs, investors could increasingly focus on Africa and Southeast Asia, where many countries suffer from food insecurity and weak land rights.

Such plantations could displace poor and marginalized communities from land they have looked after for generations but have no formal claim over, the report warned.

"Biomass plantations may also compete for the best lands with food crops (and with biofuel feedstocks), adversely affecting local food security and further marginalizing smallholder farming," it added.